CN103608712A - Imaging lens - Google Patents

Abstract

The present invention relates to an imaging lens, which comprises: a first lens with positive (+) refractive power in order from the object side; a second lens with negative (-) refractive power; and a positive (+) refractive power lens. a third lens with a positive (+) refractive power; and a fifth lens with a negative (-) refractive power, in which the aperture is inserted between the first and second lenses, and the imaging lens satisfies Conditional expression of 20<V2<30 and 50<V3, V4, V5<60, where the Abbe coefficient of the second lens is V2, the Abbe coefficient of the third lens is V3, and the Abbe coefficient of the fourth lens is V4 , and the Abbe number of the fifth lens is V5.

Description

imaging lens

technical field

Teachings according to exemplary embodiments of the present invention generally relate to an imaging lens.

Background technique

Recently, there has been an upsurge of research work in the areas of phone-purpose camera modules, digital still cameras (DSCs), camcorders (camcorders), and PC cameras (imaging devices connected to personal computers), all of which are related to image capture systems couplet. One of the most important components that enable a camera module associated with such an image capture system to obtain an image is the imaging lens that produces the image.

Previously, there was an attempt to construct a high-resolution imaging lens by using 5 lenses. Each of the 5 lenses consists of a lens with positive (+) refractive power and a lens with negative (-) refractive power. For example, an imaging lens is constructed in a structure of PNNPN (+--+-), PNPNN (+-+--), or PPNPN (++-+-) in order from the object side. However, the imaging module of this structure cannot show satisfactory optical characteristics or aberration characteristics. Therefore, high-resolution imaging lenses with new power structures are needed.

Contents of the invention

【technical problem】

Accordingly, embodiments of the present invention may relate to an imaging lens that substantially obviates one or more of the above-mentioned disadvantages/problems due to limitations and disadvantages of the prior art, and it is an object of the present invention to provide an imaging lens configured to correct an image Imaging lens that is poor and achieves sharp images.

The technical problems to be solved by the present invention are not limited to those described above, and those skilled in the art will clearly understand any other technical problems not mentioned so far through the following description.

【Technical solutions】

In an overview solution of the present invention, an imaging lens is provided, and the imaging lens includes: a first lens with positive (+) refraction power in order from the object side; a second lens with negative (-) refraction power; A third lens with positive (+) refractive power; a fourth lens with positive (+) refractive power; and a fifth lens with negative (-) refractive power; where the aperture is inserted between the first and second lenses , and the imaging lens satisfies the conditional expressions of 20<V2<30 and 50<V3, V4, V5<60, wherein the Abbe coefficient of the second lens is V2, the Abbe coefficient of the third lens is V3, and the Abbe coefficient of the fourth lens The Abbe number of the lens is V4, and the Abbe number of the fifth lens is V5.

Preferably, but not necessarily, the object-side surface of the first lens is convexly formed.

Preferably, but not necessarily, the second lens has a concave shape on the upper side surface.

Preferably, but not necessarily, the third lens, the fourth lens and the fifth lens respectively have a meniscus shape convexly formed on the upper side surface.

Preferably, but not necessarily, any one or more lenses from the first lens, the second lens, the third lens, the fourth lens and the fifth lens are aspherical.

Preferably, but not necessarily, the imaging lens satisfies the conditional expression of 0.5<f1/f<1.5, where f is the total focal length of the imaging lens, and f1 is the focal length of the first lens.

Preferably, but not necessarily, the imaging lens satisfies the conditional expression of 0.5<ΣT/f<1.5, where f is the total focal length of the imaging lens, and ΣT is the distance from the object-side surface of the first lens to the imaging surface .

Preferably, but not necessarily, the imaging lens satisfies the conditional expression of 1.6<N2<1.7, where N2 is the refractive index of the second lens.

【Beneficial effect】

The imaging lens according to the present invention has the beneficial effects of correcting aberrations and realizing a clear image by inserting a separate aperture between the first lens and the second lens, and by constructing a lens comprising the first lens, the second lens, the second lens, The imaging lens of the five lenses of the three lenses, the fourth lens and the fifth lens can reduce flash.

Description of drawings

FIG. 1 is a configuration diagram showing a camera module lens according to the present invention.

FIG. 2 is a view of measuring coma aberration according to an exemplary embodiment of the present invention.

FIG. 3 is a view illustrating aberrations according to an exemplary embodiment of the present invention.

Detailed ways

The following description is not intended to limit the invention to the form disclosed herein. Accordingly, improvements and modifications corresponding to the following teachings, and skill and knowledge of the relevant art are within the scope of the invention. The embodiments described herein are also intended to illustrate what are known modes for practicing the invention and to enable others skilled in the art to employ the invention in this or other embodiments and having a particular application or use of the invention required Various variants.

The disclosed embodiments and advantages thereof are best understood by referring to FIGS. 1-3 of the drawings, like reference numerals being used for like and corresponding parts of the various drawings. Other features and advantages of the disclosed embodiments will become apparent to those of ordinary skill in the art upon examination of the following drawings and detailed description. All such additional features and advantages are intended to be included within the scope of the disclosed embodiments and protected by the accompanying drawings. Further, the illustrated figures are merely exemplary, and are not intended to state or imply any limitation with respect to the environment, architecture, or process for implementing different embodiments. Accordingly, the described solutions are intended to embrace all such modifications, variations and improvements as fall within the scope and novel concepts of the invention.

It should be understood that when used in this specification, the terms "includes" and/or "including" specifically describe the existence of said features, regions, integers, steps, operations, elements and/or components, But it does not exclude the existence or addition of one or more other features, regions, integers, steps, operations, elements, components and/or combinations thereof. That is, the terms "comprises", "including", "has", "has", "with" or variations thereof are used in the detailed description and/or claims to mean non-exhaustive in a manner similar to "comprising" Sexual inclusion (non-exhaustive inclusion).

Also, "exemplary" is only intended to mean an example, and does not mean the best. It should also be understood that for simplicity and ease of understanding, features, layers, and/or elements described herein are shown with particular dimensions and/or orientations relative to each other, and that actual dimensions and/or orientations may be substantially different from those shown. different. That is, in the drawings, the size and relative sizes of layers, regions and/or other elements may be exaggerated or reduced for clarity. Like reference numerals refer to like elements throughout the drawings, and explanations that overlap each other will be omitted. Now, the present invention will be specifically described with reference to the accompanying drawings.

Words such as "thereby," "then," "next," "therefore," etc. are not intended to limit the order of the process; these words are simply used to guide the reader through the description of the methodology.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first region/layer could be termed a second region/layer, and, similarly, a second region/layer could be termed a first region/layer without departing from the teachings of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the general inventive concepts. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Now, an imaging lens according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a configuration diagram showing an imaging lens according to an exemplary embodiment of the present invention.

An imaging lens composed of multiple lenses is arranged with respect to the optical axis (ZO), for illustration, in Fig. 1, the thickness, size, and shape of each lens are exaggeratedly drawn, and the spherical shape or aspherical shape is only an example Examples are proposed, but obviously not limited to this shape.

Referring to Fig. 1, the camera lens module according to the present invention includes, from the object side, the first lens (10), the second lens (20), the third lens (30), the fourth lens (40), the fifth lens ( 50), a color filter (60) and a light detector (70).

The light corresponding to the image information of the object passes through the first lens (10), second lens (20), third lens (30), fourth lens (40), fifth lens (50) and color filter (60) on the light detector (70).

The imaging lens according to the present invention includes five lenses, including a first lens (10), a second lens (20), a third lens (30), a fourth lens (40) and a fifth lens (50), so that according to the present invention The inventive imaging lens has the beneficial effects of correcting aberrations and realizing clear images by inserting a separate aperture between the first lens and the second lens, and by constructing a The imaging lens of 5 lenses including the fourth lens, the fourth lens and the fifth lens can reduce flare.

Hereinafter, in the description of the configuration of each lens, the "object side surface" means the surface of the lens facing the object side with respect to the optical axis, and the "image side surface" means the imaging surface facing with respect to the optical axis surface of the lens. And "upper side surface" refers to the surface of the lens facing the photographing surface with respect to the optical axis.

In the specification, "imaging" can basically refer to a process in which an imaging lens receives light from an object in a field of view and outputs an image (image signal and image data) representing the object. However, if the imaging lens repeatedly generates images representing objects in the field of view at a predetermined cycle, "imaging" may refer to a process of storing a specific image among images generated by the imaging lens in a storage unit. In other words, from a specific standpoint, "imaging" may refer to a process in which an imaging lens acquires an image showing the contents of an object in the field of view at a specific desired timing, and the image has the content.

The first lens (10) has positive (+) refractive power, and is convexly formed at the object side surface (S1). The second lens ( 20 ) has negative (-) refractive power, and is concavely formed on the upper side surface ( S4 ). Also, a separate aperture is inserted between the first lens and the second lens (10, 20). In addition, the third lens and the fourth lens (30, 40) have positive (+) refractive power, and the fifth lens (50) has negative (-) refractive power. As shown, the third lens (30) has a meniscus convexly formed on the upper surface (S6), the fourth lens (40) has a meniscus convexly formed on the upper surface (S8), And the fifth lens (50) has a meniscus shape convexly formed on the upper side surface (S19).

For reference, 'S2' of Figure 1 is the upper side surface of the first lens (10), 'S3' is the object side surface of the second lens (20), 'S5' is the upper side surface of the third lens (30) , 'S7' is the object-side surface of the fourth lens (40), 'S9' is the object-side surface of the fifth lens (50), and 'S11' and 'S12' are the object-side surfaces and upper surface.

Also, one or more of the first to fifth lenses ( 10 , 20 , 30 , 40 , 50 ) may be formed with an aspherical shape. The color filter (60) can be any optical color filter selected from infrared color filters and glass cover plates. If an infrared filter is applied, the filter (60) blocks the transfer of radiant heat from external light to the photodetector (70). Also, the infrared filter transmits visible light, reflects infrared rays and outputs them to the outside.

The photodetector ( 70 ) is an image sensor such as CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) or the like.

The first lens (10), the second lens (20), the third lens (30), the fourth lens (40) and the fifth lens (50) respectively use aspherical lenses as described in the exemplary embodiments below, In order to improve the resolution of the lens as much as possible, and has excellent aberration characteristics.

Also, the imaging lens of the present invention is formed with an aperture interposed between the first lens (10) and the second lens (20) to reduce flicker and determine a stable CRA (Chief Ray Angle) curve, and realizes High image quality.

Since the conditional expressions and exemplary embodiments described later are preferred embodiments for enhancing the interaction effect, it will be apparent to those skilled in the art that the present invention does not necessarily include the following conditions. For example, the lens configuration (framework) of the present invention can have an enhanced interaction effect only by satisfying some conditions of conditional expressions described later.

[conditional expression 1] 0.5<f1/f<1.5

[Conditional Expression 2] 0.5<∑T/f<1.5

[conditional expression 3] 1.6<N2<1.7

[conditional expression 4] 20<V2<30

[Conditional expression 5] 50<V3, V4, V5<60

Among them, f: the total focal length of the imaging lens

f1: focal length of the first lens

∑T: Distance from the object-side surface of the first lens to the imaging surface

N2: Refractive index of the second lens

V2, V3, V4, V5: Abbe coefficients of the second to fifth shots

Conditional Expression 1 specifically describes the refractive power of the first lens ( 10 ), according to which the refractive power of the first lens ( 10 ) has appropriate spherical aberration compensation and appropriate chromatic aberration. Conditional Expression 2 specifically describes the scale of the optical axis direction of the entire optical system, and Conditional Expression 2 is a condition for an ultra-small lens and a condition for appropriate aberration compensation.

Conditional expression 3 specifically describes the refractive index of the second lens (20), conditional expression 4 specifically describes the Abbe coefficient of the second lens (20), and conditional expression 5 specifically describes the third lens, the fourth lens, and the fifth lens The Abbe number of the lens (30, 40, 50). The specific description of Abbe's number for each lens is the condition for better chromatic aberration compensation.

Hereinafter, actions and effects of the present invention will be described with reference to specific exemplary embodiments. The aspheric surface mentioned in the exemplary embodiment hereinafter is obtained from the known equation 1, and E and the subsequent The number ˊ represents the 10th power. For example, E+01 means 101 and E-02 means 10-2.

【Equation 1】

$\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="cY"\; filenames="HDA0000433922170000011.png,HDA0000433922170000021.png"\; state="\{\{state\}\}">cY</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="Y"\; filenames="HDA0000433922170000011.png,HDA0000433922170000021.png"\; state="\{\{state\}\}">Y</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="4"\; label="AY"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">AY</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="4"\; label="B\; Y"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">B</figure-callout></span><figure-callout\; id="4"\; label="B\; Y"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">\; </figure-callout>}{\mathrm{<span\; class="notranslate">\; </span>}}^{}{\mathrm{<span\; class="notranslate">Y</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="4"\; label="Cy"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">Cy</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="4"\; label="Dy"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">Dy</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="4"\; label="EY"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">EY</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="4"\; label="f\; Y"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">f</figure-callout></span><figure-callout\; id="4"\; label="f\; Y"\; filenames="HDA0000433922170000011.png"\; state="\{\{state\}\}">\; </figure-callout>}{\mathrm{<span\; class="notranslate">\; </span>}}^{}{\mathrm{<span\; class="notranslate">Y</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>$

Among them, z: the distance from the vertex of the lens to the direction of the optical axis, c: the basic curvature of the lens, Y: the distance towards the direction perpendicular to the optical axis, K: the quadratic constant, and A, B, C, D, E , F: aspheric coefficient

[Exemplary embodiment]

Table 1 below shows exemplary embodiments that match the aforementioned conditional expressions.

[Table 1]

exemplary embodiment f 4.13 f1 2.56 f2 -3.64 f3 9.73 f4 10.25 f5 -5.79 │f2/f1│ 1.42 ΣT 4.7 ΣT/f 1.138

Referring to Table 1, note that f1/f is 0.619, matching conditional expression 1, and ΣT/f is 1.138, matching conditional expression 2.

Table 2 below shows more detailed exemplary embodiments than those of Table 1.

[Table 2]

The symbol * written next to the surface number in the above Table 2 and the following Table 3 indicates an aspheric surface. Table 3 below shows values of aspheric coefficients of each lens in the exemplary implementation of Table 2.

[table 3]

【Detailed ways】

As a graph for measuring coma aberration, FIG. 2 is a graph showing coma aberration according to an exemplary embodiment of the present invention, in which tangential aberration (tangential aberration) and radial aberration for each wavelength are measured based on the height of field of view. Aberration (sagittal aberration). In FIG. 2, since the curves approach the X-axis from the positive axis and the negative axis, this indicates that the coma aberration correction function is good. In the aberration diagram shown, since image values in almost all fields are close to the X-axis, the coma aberration correction function shows an excellent shape.

FIG. 3 is a graph showing aberrations according to an exemplary embodiment of the present invention. That is, FIG. 3 is a diagram in which longitudinal spherical aberration, an astigmatism field curve, and distortion are measured sequentially from the left. In Figure 3, the Y axis refers to the size of the image, while the X axis refers to the focal length (unit: mm) and distortion (unit: %). In FIG. 3, since the curve approaches the Y axis, it means that the aberration correction function is good. In the shown aberration graphs, longitudinal spherical aberration, astigmatism field curve, and distortion all show excellent shapes because image values in almost all fields appear close to the Y axis.

That is, the range of longitudinal spherical aberration is -0.007㎜～+0.008㎜, the range of astigmatism field curve is -0.018㎜～+0.004㎜, and the range of distortion is 0.00㎜～+1.00㎜, so that the imaging lens according to the present invention The characteristics of longitudinal spherical aberration, astigmatism field curve and distortion can be corrected, so that the imaging lens according to the present invention has excellent lens characteristics.

The preceding description of the invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to the invention will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other modifications without departing from the spirit and scope of the invention. Thus, the invention is not intended to limit the examples described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

【Industrial Applicability】

As is apparent from the foregoing, the imaging lens according to the exemplary embodiments of the present invention has industrial applicability in correcting aberrations and realizing sharp images by inserting a separate aperture between the first lens and the second lens , and by constructing an imaging lens having 5 lenses including a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, flicker can be reduced.

Claims (8)

1. An imaging lens, said imaging lens comprising: a first lens with positive (+) refractive power in order from the object side; a second lens with negative (-) refractive power; and a positive (+) refractive power a third lens having a positive (+) refractive power; and a fifth lens having a negative (-) refractive power; wherein an aperture is inserted between said first lens and said second lens, and The imaging lens satisfies the conditional expressions of 20<V2<30 and 50<V3, V4, V5<60, wherein the Abbe coefficient of the second lens is V2, the Abbe coefficient of the third lens is V3, and the Abbe coefficient of the fourth lens is The Abbe number is V4, and the Abbe number of the fifth lens is V5. 2. The imaging lens according to claim 1, wherein an object-side surface of the first lens is convexly formed. 3. The imaging lens according to claim 1, wherein the second lens has a concave shape at an upper side surface. 4. The imaging lens according to claim 1, wherein the third lens, the fourth lens, and the fifth lens respectively have a meniscus shape convexly formed on an upper side surface. 5. The imaging lens according to claim 4, wherein any one or more lenses from the first lens, the second lens, the third lens, the fourth lens, and the fifth lens The lens is aspherical. 6. The imaging lens according to claim 1, wherein the imaging lens satisfies the conditional expression of 0.5<f1/f<1.5, wherein f is the total focal length of the imaging lens, and f1 is the first lens focal length. 7. The imaging lens according to claim 1, wherein the imaging lens satisfies the conditional expression of 0.5<∑T/f<1.5, where f is the total focal length of the imaging lens, and ∑T is from the The distance from the object-side surface of the first lens to the imaging surface. 8. The imaging lens according to claim 1, wherein the imaging lens satisfies a conditional expression of 1.6<N2<1.7, where N2 is a refractive index of the second lens.

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